A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to de Havilland DHC-6 series airplanes that do not have Modification No. 6/1769 incorporated was published in the Federal Register on October 3, 1994 (59 FR 54412). The action proposed to supersede AD 81-10-11 with a new AD that would (1) retain the current requirement of inspecting the elevator root rib for cracks, and replacing any cracked part; and (2) require modifying the elevator root rib (Modification 6/1769) as terminating action for the repetitive inspections. Accomplishment of the proposed actions would be in accordance with de Havilland Service Bulletin No. 6/399, Revision E, dated May 25, 1984.
Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposed rule or the FAA's determination of the cost to the public.
After careful review of all available information related to the subject presented above including the referenced service information, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed except for minor editorial corrections. The FAA has determined that these minor corrections will not change the meaning of the AD and will not add any additional burden upon the public than was already proposed.
The FAA estimates that 169 airplanes in the U.S. registry will be affected by this AD, that it will take approximately 54 workhours per airplane to accomplish the required action, and that the average labor rate is approximately $60 an hour. Parts cost approximately $4,200 per airplane. Based on these figures, the total cost impact of this AD on U.S. operators is estimated to be $1,257,360. This figure is based on the assumption that none of the affected airplane owners/operators have incorporated Modification 6/1769.
The intent of the FAA's aging commuterairplane program is to ensure safe operation of commuter-class airplanes that are in commercial service without adversely impacting private operators. Of the approximately 169 airplanes in the U.S. registry that will be affected by this AD, the FAA has determined that approximately 50 percent are operated in scheduled passenger service. A significant number of the remaining 50 percent are operated in other forms of air transportation such as air cargo and air taxi.
The following paragraphs present cost scenarios for airplanes where no cracks were found and where cracks were found, utilizing an average remaining airplane life of 15 years and an average annual utilization rate of 1,600 hours time-in-service (TIS). De Havilland Models DHC-6-100 and DHC-6-200 airplanes have probably already accumulated 15,000 hours TIS; therefore, those airplanes would have 100 hours TIS after the effective date of the AD to incorporate Modification 6/1769. Some Model DHC-6-300 airplanes have not yet accumulated 15,000 hours TIS. This analysis is based upon the assumption that those airplanes yet to accumulate 15,000 hours TIS have 10,000 hours TIS if operated in scheduled service and 5,000 hours TIS if operated in general aviation. A copy of the full Cost Analysis and Regulatory Flexibility Determination for this action may be examined at the FAA, Central Region, Office of the Assistant Chief Counsel, Attention: Rules Docket No. 91-CE-22-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri.
o No Cracks Scenario for Models DHC-6-100 and DHC-6-200: These airplanes will be inspected at 50 hours TIS after the effective date and modified within 100 hours TIS after the effective date. The incremental present value cost of this AD over that required by AD 81-10-11 is $5,919 for an airplane utilized in scheduled service, and $6,642 for an airplane utilized in general aviation.
o No Cracks Scenario for Model DHC-6-300 Airplanes: These airplanes will be inspected at 50hours TIS after the effective date and thereafter at 600-hour TIS intervals until the elevator root rib is replaced upon the accumulation of 15,000 hours TIS. The incremental present value cost of this AD over that required by AD 81-10-11 is $4,962 for an airplane utilized in scheduled service, and $3,099 for an airplane utilized in general aviation.
The Regulatory Flexibility Act of 1980 (RFA) was enacted by Congress to ensure that small entities are not unnecessarily or disproportionally burdened by government regulations. The RFA requires government agencies to determine whether rules will have a "significant economic impact on a substantial number of small entities," and, in cases where they could, conduct a Regulatory Flexibility Analysis in which alternatives to the rule are considered. FAA Order 2100.14A, Regulatory Flexibility Criteria and Guidance, outlines FAA procedures and criteria for complying with the RFA. Small entities are defined as small businesses and smallnot-for-profit organizations that are independently owned and operated or airports operated by small governmental jurisdictions. A "substantial number" is defined as a number that is not less than 11 and that is more than one-third of the small entities subject to a rule, or any number of small entities judged to be substantial by the rulemaking official. A "significant economic impact" is defined by an annualized net compliance cost, adjusted for inflation, which is greater than a threshold cost level for defined entity types. FAA Order 2100.14A sets the size threshold for small entities operating aircraft for hire at 9 aircraft owned and the annualized cost thresholds, adjusted to 1994 dollars, at $69,000 for scheduled operators and $5,000 for unscheduled operators.
Of the 169 U.S.-registered airplanes affected by this AD, six airplanes are owned by the federal government. Of the other 163 airplanes, one business owns 26 airplanes, two businesses own 9 airplanes each, one business owns 8 airplanes, one business owns 7 airplanes, one business owns 5 airplanes, four businesses own 3 airplanes each, sixteen businesses own 2 airplanes each, and fifty-five businesses own 1 airplane each.
Because the FAA has no readily available means of obtaining data on the sizes of these entities, the economic analysis for this AD utilizes the worst case scenario using the lower annualized cost threshold of $5,000 for operators in unscheduled service instead of $69,000 for operators in scheduled service. With this in mind and based on the above ownership distribution, this AD could have a significant impact on a substantial number of small entities. Because of this, the FAA conducted a regulatory flexibility analysis. A copy of this analysis may be obtained by contacting the Rules Docket at the location provided under the caption "ADDRESSES".
The regulations adopted herein will not have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, may have a significant economic impact on a substantial number of small entities. The FAA has conducted an Initial Regulatory Flexibility Determination and Analysis and has considered alternatives to this action that could minimize the impact on small entities. A copy of this analysis may be obtained by contacting the Rules Docket at the location provided under the caption "ADDRESSES". After careful consideration, the FAA has determined that the required action is the best course to achieve the safety objective of returning the airplane to its original certification level of safety.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:
PART 39 - AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 USC 106(g), 40101, 40113, 44701.
Section 39.13 - [AMENDED]
2. Section 39.13 is amended by removing Airworthiness Directive (AD) 81-10-11, Amendment 39-4112, and adding a new AD to read as follows: